This invention relates to computer systems, and, more particularly, to the connection of peripheral devices to computers.
One of the important features of computers is their ability to connect to, exchange information with, and control (and be controlled by) various accessories. In some cases, accessories are internal to the computer. In other cases, due to size or other requirements, the accessories are external to the computer.
If the computer is a large desk-top type computer, many accessories may be provided within the body of the computer. If the computer is a portable computer such as laptop or notebook computer, some accessories must be furnished external to the computer because of their size, weight, and/or power requirements. Examples of such external accessories, termed "peripheral devices" herein, include modems for communicating through telephone lines with other computers, local area networks of two or more computers, and SCSI interfaces with machinery or devices.
The various types of peripheral devices typically utilize different connector structures, according to conventions established for each such device. According to the current conventions, modems use an RJ-11 connector, local area networks use an RJ-45 connector, and SCSI interfaces use a 50-pin Centronics connector. The selection of these different connectors is not arbitrary, but is made responsive to the requirements of the various peripheral devices.
In the conventional approach for interfacing a portable computer to such a peripheral device, a special-purpose PCMCIA card plugs into the computer. Since many of the integrated circuits required for peripheral interfaces are physically too large to reside inside the PCMCIA card, the interface is typically split into two pieces, the PCMCIA card itself and an outboard assembly, commonly termed a "dongle". The PCMCIA card contains a portion of the electronics required to interface the computer to the peripheral device, as well as the logic required to create an intermediate bus-like interface to communicate between the PCMCIA card and the dongle. The remaining interface electronics, as well as the interface to the intermediate bus, are placed in the dongle. The outboard assembly is usually in the form of a cable that plugs into the PCMCIA card at one end and the peripheral device at the other end. The PCMCIA card and the outboard assembly cable thus cooperate to interface the computer to the peripheral device, both electronically and physically by providing the required pin connector configurations. The PCMCIA card and the outboard assembly cable are special-purpose devices useful only with the peripheral device for which they are designed.
When the computer user wishes to add a peripheral device to the capability of the computer, the PCMCIA card and the outboard assembly cable are purchased along with the other structure and software of the peripheral device. In some instances, such as the modem, the cost of the dedicated PCMCIA card and the outboard assembly cable can constitute a significant portion of the total cost of the peripheral device. When the computer user adds another peripheral device to the computer capability, a separate dedicated PCMCIA card and outboard assembly cable specific to that device are purchased.
The present inventor has recognized a need for an improved approach to interfacing peripheral devices to computers, particularly portable computers. Such an interfacing approach would desirably reduce the cost of interfacing various types of peripheral devices to the computer, while managing the power requirements for the peripheral devices and the computer. The present invention fulfills this need, and further provides related advantages.